This invention relates to the processing of coffee beans to make roast and ground coffee. More particularly, it relates to a process for making a reduced density roast and ground coffee product having a less chaffy appearance.
In the standard roast and ground coffee process, roasted coffee beans are cracked, then ground, and then normalized. Cracking breaks the beans into very large pieces and releases the chaff. During the grinding step the pieces of ground coffee and chaff are broken into smaller pieces. Since the surface area increases, more of the naturally occurring coffee oil is exposed. The normalizer is a mixing chamber with rotating paddles which beat the light-colored chaff into tiny fragments and mix them with the dark-colored coffee oil. Normalization gives the coffee a better appearance because the small, darkened chaff particles are more difficult to see against the background of the ground coffee beans.
Normalization has the additional effect of densifying the coffee because the mixing rounds off the edges of the coffee particles, allowing them to pack closer and more efficiently together. This densifying effect of normalization is a problem if one wishes to produce a lower density coffee product. Air removal or screening can be used instead of normalization to deal with the chaff problem; however, with air removal the small coffee particles are lost with the chaff, and with screening the small pieces of chaff are not removed. These alternatives to normalization are thus imperfect solutions to the chaff problem.
U.S. Pat. No. 4,349,573 to Stefanucci et al., issued Sept. 14, 1982, discloses a process for making a low density coffee. The process comprises: (a) preparing a roasted high quality coffee bean fraction under short roasting conditions effective to produce a roasted high quality coffee bean fraction having a roast color of no more than 50 and a bulk density less than 0.35 g/cc; (b) preparing a roasted intermediate quality coffee bean fraction under short roasting conditions effective to produce a roasted intermediate quality coffee bean fraction having a roast color of 60 and a bulk density less than 0.32 g/cc; (c) preparing a roasted low quality coffee bean fraction under short roasting conditions effective to produce a roasted low quality coffee bean fraction having a roast color of 85 and a bulk density less than 0.40 g/cc; (d) blending the roasted fractions of steps (a), (b) and (c) in a ratio effective to produce a ground blend having a maximum free flow density of 0.30 g/cc and wherein the high quality coffee constitutes 25-40%, the intermediate quality coffee constitutes 50-60% and the low quality coffee constitutes 10-15% of the final blend; (e) grinding the roasted blend of step (d), while bypassing the grinder normalizer, to an average particle size of 880-900 microns for electric percolator grind; of 830-850 microns for stove percolator grind; or of 740-760 microns for automatic drip grind.
In the Stefanucci et al. process the ground beans are not normalized. While this process produces a low density coffee, the low density is achieved by avoiding the normalization step altogether. This results in a chaffy appearance in the ground product. The chaff must then be removed using air or screens (with their inherent problems discussed above), or it can be left in the coffee, creating an unacceptable appearance.
Hence, there is a need for a process of making a reduced density roast and ground coffee in which the chaff problem is addressed by a method other than by eliminating the normalization step.
It is therefore an object of the this invention to provide a process which retains the normalization step but still produces a low density coffee.
It is another object of this invention to produce a reduced density roast and ground coffee having a non-chaffy appearance.
These and other objects of the invention will become clear by the disclosure herein.